Frogs' Tongues: Sticky Tape-Like Muscles Pick Up Prey With Ease

Frogs have pretty weird tongues, right? If you have ever seen a frog throw its tongue out to snatch up its prey, I am sure you would agree. Frogs' tongues are much different than humans. For starters, a frog's tongue is attached to the front of their mouths rather than at the back. When a frog sees an insect flying by it shoots its sticky tongue into the air and wraps it around its prey. The tongue quickly snaps back and throws the food down the frog's throat. Now, scientists from Kiel University have taken a closer look at this hunting style.

Researchers examined what happens when a frog's tongue makes contact with a surface, and it turns out it is similar to modern adhesive tape. That is, a frog's tongue forms many little threads (fibrils) when being removed from a surface. These threads break one at a time before the contact disconnects.

"We got horned frogs to spit their tongues towards a cricket, which was placed behind a sheet of glass," Dr. Thomas Kleinteich, of the Zoological Institute at Kiel University, said in a news release.

The transparent glass was connected to a light source, which lit up the places the tongue came into contact with. Researchers filmed these lit areas using a high-speed camera that allowed them to closely observe exactly how the contact formed between the frog's tongue and its "prey," before disconnecting.

Researchers also investigated how individual muscle fibers on a frog's tongue were arranged using previous research of frog anatomy and 3D models. From this, they found that the muscle used to pull the tongue back into the frog's mouth literally fans out under the surface of the tongue. As the frog retracts its tongue, the force is spread evenly over the entire surface of the tongue, according to the news release.

"This is a similar effect to trying to vertically pull a strip of Sellotape (sticky tape) off a surface, instead of starting from one end -- you need significantly more strength to do so," Kleinteich added in a statement.